Development of various electronic devices has been accompanied with market requirement about more excellent operability. Portable electronic devices such as cellular phones and digital still cameras have been required to be further downsized and light-weighted, and yet, an improvement in usability has been also needed.
A cellular phone taken as an example of conventional electronic devices is described hereinafter. FIG. 11 is an perspective appearance of a general cellular phone. First enclosure 1 and second enclosure 2 are hinged together and are foldable. Display 3 is placed inside first enclosure 1, and a top face of second enclosure 2 works as operator panel 2a for manipulating various functions. A controller (not shown) is placed inside second enclosure 2 for controlling operations through an input to operator panel 2a. 
On operator panel 2a, operating keys are arranged such that multi-directional operating section (key) 4 and enter keys 5 are placed forward, and ten-key 6 is placed backward. Each one of the respective keys has a push switch (not shown) provided on a circuit board placed in second enclosure 2 and an operating button which prompts the push switch from the top to work.
Multi-directional key 4 is formed of four push switches assigned to front, back, left and right directions and one operating button which prompts the four push switches to work. Depressing a disk-like operating button protruding from panel 2a at its front, back, left or right position results in obtaining a switch signal corresponding to the position depressed.
Enter keys 5 are placed on both sides of multi-directional key 4 respectively. Pressing the operating buttons protruding from panel 2a results in obtaining a switch signal corresponding to the push switch placed under the operating button.
Ten-key 6 includes operating buttons arranged on three rows and four lines. Pressing each one of the operating buttons protruding from panel 2a results in obtaining a switch signal corresponding to each one of the push switches placed under the respective operating buttons.
In the conventional electronic device, signals from the respective switches are supplied to the controller placed in second enclosure 2, and the controller controls a content to be displayed on display 3 and various functions. When a user operates operator panel 2a in a given way, various information is displayed on display 3, then the user selects a desirable item or a function and enters it through enter key 5 for execution.
A displayed condition on display 3 is described hereinafter. A telephone number is taken as an example of a display on display 3. Choices such as telephone numbers to be selected are displayed in a format of one choice by one line as shown in FIG. 12, and a selected one is usually indicated with cursor 7. Only a part of the respective choices is usually displayed due to a limited area of display 3. In such a case, the user needs to read the hidden part by depressing multi-directional key 4 at its left or right position to scroll the displayed content in a lateral direction through the control by the controller. A choice of lines in a vertical direction needs to depress key 4 at its front or back position to scroll the displayed content in the vertical direction, and the controller controls the display in the vertical direction accordingly.
The user selects a line and puts cursor 7 to the selected choice, then depress enter key 5. This operation sends a switch signal corresponding to the selected item to the controller, which then confirms the selected choice, or executes a move to a menu on the lower level.
Recently, a cellular phone has been sophisticated, which is accompanied with increment of functions available to users, and yet, the usability of those functions has been improved. As a result, functions and choices to be displayed on display 3 are increasingly symbolized using an icon instead of describing them in the format of one choice by one line.
A display using icons is described with reference to FIG. 13. On display 3, pointer 8 (indicated with an arrow mark) is displayed and various icons 9 are displayed in a given arrangement.
In FIG. 13, eight icons 9 are schematically arranged equidistantly shaping like a square on display 3. To be more specific, three icons are arranged equidistantly on a upper line and a lower line respectively, and two icons are placed on a middle line except at the center position. Depressing multi-directional key 4 at its front, back, left or right position prompts pointer 8 to move to the choice selected, because a switch signal corresponding to the depressing is sent to the controller, which then moves pointer 8 accordingly.
In such an electronic device, depressing multi-directional key 4 at its front, back, left, or right position moves pointer 8 to a desirable choice, then entry key 5 is depressed. This operation prompts the controller to execute a control in response to the switch signal transmitted, thereby executing a function assigned to icon 9 selected, or executing a move to a menu on the lower level.
The foregoing prior art is disclosed in, e.g. Japanese Patent Unexamined Publication No. 2002-351598.
The progress of a slimmer and lighter body of the conventional cellular phone entails use of the switches shown in FIG. 14 or FIG. 15 as multi-directional key 4. To be more specific, a set of four fixed contacts 11 of the switch is placed on circuit board 10 in second enclosure 2, and domed movable contact 12 for on/off is mounted to the respective fixed contacts 11. This type of switch has been employed mainly in the cellular phones. The structure of the switch discussed above makes the body advantageously slim; however, use of four individual switches needs structural elements for four ones, and is resistant to a decrease in the number of components. Amid such circumstances, users of the cellular phone still need further improvement in the usability.